Are wind power and ranching compatible? The proof is sticking to the bottom of my boot. While hiking around the Ponnequin Wind Facility in far northern Colorado, I stepped in the soft calling card of a well-fed bison.

The bison belongs to a neighbor of Keith and Myrna Romans, who own most of the land where the Xcel Energy Corporation planted Colorados first commercial crop of wind turbines in 1996. There are 44 turbines now, spread along a dry, wind-whipped ridge in Weld County. They resemble the enormous white columns of a Greek temple, overlooking the Front Range to the south and Wyomings capital city, Cheyenne, to the north.

"You see how quiet it is?" says Keith Roman, standing at the base of one of the towers. Indeed, theres only a gentle whoosh as the rotors sweep around. "The noise doesnt bother the cattle, or the antelope," says Myrna. Or the bison, apparently.

The Romans, who live in Wyoming, have owned these 420 acres just across the Colorado border for 45 years. Their first ranch animal was a milk cow, and when she calved they were on their way to a herd of 120 or so. Like most small-scale ranchers, the Romans worked other jobs as well, all for the pleasure of rising before dawn and working into the night. When someone inquired about leasing their high ground for wind turbines, they werent surprised, having stood up there in howling blizzards.

Myrna points at the turbines, which are pivoting to face the southwest wind. Inside are computers that control the direction, rotor speed, and pitch of the blades. Collectively, Ponnequins turbines produce 30 megawatts of electricity, which Xcel sells to some 21,000 subscribers who pay an extra 2.5 cents per kilowatt-hour for the "green" wind energy. The only complaint from neighbors, says Myrna, has been about the blinking lights atop the towers that warn low-flying aircraft.

The turbine technology employed on the Romans ranch is much more sophisticated than earlier wind farms in California, which chopped up passing raptors. The key was to slow rotor speed and site the turbines away from customary flight paths. Robert Ryder, a biologist from Colorado State University in Fort Collins, scouts the Ponnequin facility for injured wildlife. "We havent seen nearly the impact we expected from the California data," he says. Last year Ryder found seven dead birds at the site, including only one raptor, an American kestrel. (The impact on bats was greater17 dead.) And worries that pronghorn would be spooked proved unfounded. "They seem to like it because its safetheres no hunting allowed," says Ryder.

Last year was a banner one for commercial wind energy in the United States, with production from facilities in 26 states rising 60 percent to 4,261 megawatts (enough to supply more than a million people). The American Wind Energy Association estimates that new wind farms in 2002 will eliminate emissions of 7.5 million tons of carbon dioxide from fossil-fuel power plants. Industry experts say that wind energy could provide over 5 percent of the nations electricity by 2020.

For the Romans, it provides extra retirement income as well, though they wont reveal exactly how much. "I can tell you were making much more off this than we did off cows," says Keith, chuckling. "And, you dont have to feed them, you dont have to break ice, and you dont have to calve them out." Geoffrey OGara